Luliconazole is an antifungal agent which is excellent in the action on fungi. At present, luliconazole is widely used as a pharmaceutical or medicine for tinea pedis and tinea corporis, and it is going to be applied also for the action on tinea unguium. In relation to the pharmaceutical preparation (medicament preparation) of luliconazole, it is known as problems which should be solved that luliconazole is converted to stereoisomers, such as the SE isomer and the Z isomer, and that the crystallization of luliconazole is caused immediately after the application (see, for example, Patent Documents 1 to 6). In particular, as for the isomerization, the present inventors have confirmed that the stereoisomerization to the SE isomer or the Z isomer is influenced by components in pharmaceutical preparations, the temperature, and the light. Reflecting the circumstances as described above, a storage condition of 3 weeks at 60° C. is used to evaluate the stability of luliconazole. In this way, it has been necessary that the heating step is shortened as much as possible in the production of luliconazole. However, luliconazole has poor solubility in aqueous media. Therefore, it is required in the formulation of luliconazole that the dissolving step with heating, stirring and other operations is applied. Consequently, it has been demanded to develop any means for improving the solubility of luliconazole and shortening the heating time in the dissolving step. Shortening or reducing the time required in dissolving step has advantages that induce not only the inhibition of the generation or formation of any isomer in this step but also the long-term stabilization obtained by the contribution of lowering the initial value of the isomer amount. In other words, it is affirmed that shortening or reducing the time required in the dissolving step results in the great improvement in the quality.
On the other hand, as for crystals of luliconazole, it is known that the crystals are obtained by recrystallization from a mixture of ethyl acetate and n-hexane (see Patent Document 7). However, nothing is known at all about details of the crystallographic properties such as a crystal system. Further, nothing is known at all about recrystallization from alcohol or the like.